JPH0667116U - Vehicle air suspension system - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the roll in a vehicle air suspension device having a sub tank without reducing the riding comfort. [Configuration] Only when the vehicle speed V is equal to or higher than a predetermined vehicle speed Vx (S3) and the steering angle θ is equal to or higher than a predetermined steering angle θx (S4),
If the vehicle is steered greatly at a high speed and roll is likely to occur, the electromagnetic valve 7 is controlled to be closed (S5), and the communication between the inside of the air spring 3 and the sub tank 6 is cut off. Here, the smaller the air volume of the air spring 3 is, the more the internal pressure is increased. Therefore, the reaction force is increased, the spring constant is increased, and the roll is less likely to be generated.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vehicle air suspension device, and more particularly to a vehicle air suspension device having a sub tank.

[0002]

[Prior art]

 Conventionally, as one of suspensions mounted on a bus or a large truck, a vehicle that supports a vehicle body by utilizing air elasticity as disclosed in, for example, Japanese Utility Model Publication No. 64-52920 or Japanese Utility Model Publication No. 2-141510. Air suspension devices for vehicles are known.

That is, as shown in FIG. 5, between the sprung portion and the unsprung portion, that is, between the vehicle body A (not shown) and the front tires F1 and F2 (not shown), and the vehicle body A (not shown) and the rear tire R1 (not shown). , R2, R3, R4 are provided with air springs 3 _F1 , 3 _F2 , 3 _R1 , 3 _R2 , 3 _R1 and 3 _R2, respectively. For simplicity, the air spring 3 will be described below.

Next, the air system related to the vehicle air suspension device will be described. The air pressurized by the air compressor 11 is removed from the water content in the air by the air dryer 12, and then the air reservoir tank. Stored in 13. The pressure in the air reservoir tank 13 is adjusted to a predetermined pressure by the governor 14. The compressed air stored in the air reservoir tank 13 is sent to the air spring 3 via the leveling valve 4 of the air spring 3.

Then, the leveling valve 4 adjusts the degree of filling of the compressed air in each of the air springs 3 according to the increase or decrease of the load, and when the vehicle height decreases, the leveling valve 4 causes the air reservoir tank 13 and each of the air springs 3 to move. When the vehicle height rises, the leveling valve 4 opens to the exhaust side to exhaust the air in each air spring 3 and lower the vehicle height. .

In a bus or a truck equipped with the vehicle air suspension device as described above, the vehicle body swings during traveling, so that the leveling valve 4 operates to keep the vehicle body horizontal. Then, the compressed air in each air spring 3 is supplied and exhausted.

[0007]

[Problems to be solved by the device]

 Recently, there is a need to further improve the riding comfort, and for this reason, there is a vehicle air suspension device having a sub tank 6 which communicates with the inside of the air spring 3 via a pipe 5. That is, in the air spring 3, the inside of the air spring 3 and the sub tank 6 are integrated to increase the air volume inside the air spring 3. Since the larger the air volume is, the smaller the increase in internal pressure with respect to the displacement is, the reaction force of the air spring 3 is reduced, thereby reducing the spring constant and improving the riding comfort.

However, if the spring constant is reduced, the riding comfort is improved, but the swing of the vehicle body is increased. For this reason, a stabilizer or the like has been mounted as a roll reducing means, but this may have a bad influence on the riding comfort, and may increase the vehicle weight to deteriorate the fuel efficiency. The present invention has been made in view of the above circumstances, and an object thereof is to reduce rolls in a vehicle air suspension device having a subtank without reducing riding comfort.

[0009]

[Means for Solving the Problems]

 Therefore, the present invention provides an air suspension device for a vehicle, which includes an air spring between an unsprung part and an unsprung part, and has a sub-tank communicating with the inside of the air spring. Means, a vehicle speed detecting means for detecting a vehicle speed, a steering angle detecting means for detecting a steering angle of the steering wheel, and a control means for controlling the opening / closing means to be closed when the vehicle speed and the steering angle of the steering wheel are above a predetermined value. Is provided.

[0010]

[Action]

 In the air spring, the larger the air volume is, the smaller the increase in internal pressure with respect to the displacement is. Therefore, the reaction force of the air spring is small, and thus the spring constant is small. On the other hand, the smaller the air volume, the greater the increase in internal pressure, and the greater the reaction force, the greater the spring constant, and the less likely rolls are generated.

Here, when the vehicle speed and the steering angle of the steering wheel are equal to or higher than a predetermined value by the respective detection means, it means that the vehicle is in a driving state in which the steering wheel is largely steered at a speed equal to or higher than a predetermined speed, and there is a fear of a large roll. By controlling the opening / closing means for opening / closing the communication between the inside and the sub tank, the air volume in the air spring is limited to the inside of the air spring to increase the spring constant and suppress the occurrence of rolls.

Therefore, it is possible to suppress the roll generation at high speed.

[0013]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. First, the system configuration according to the present embodiment will be described with reference to FIG. 1. However, the same components as those in the above-described conventional example are designated by the same reference numerals as those in FIG. In the figure, as a configuration according to the present invention, a solenoid valve 7 as an opening / closing means is interposed in a pipe 5 that connects the inside of the air spring 3 and the sub tank 6.

Further, as shown in FIG. 2, the solenoid valve 7 is controlled to open and close the communication of the pipe 5 by a control signal from a control unit 31 having a built-in microcomputer. The vehicle speed V from the vehicle speed sensor 32 as the vehicle speed detecting means and the steering angle θ of the steering from the steering angle sensor 33 as the steering angle detecting means are input.

Next, the open / close control of the solenoid valve 7 by the control unit 31 will be described with reference to the flowchart shown in FIG. In step 1 (denoted as S1 in the figure. The same applies hereinafter), the steering angle θ of steering from the steering angle sensor 33 is read. In step 2, the vehicle speed V from the vehicle speed sensor 32 is read.

In step 3, it is determined whether the vehicle speed V is equal to or higher than a predetermined vehicle speed Vx. In step 4, it is determined whether or not the steering angle θ is equal to or larger than the predetermined steering angle θx. Then, only when the vehicle speed V is equal to or higher than the predetermined vehicle speed Vx and the steering angle θ is equal to or higher than the predetermined steering angle θx, the process proceeds to step 5. In step 5, the steering is largely steered when the vehicle is in a high speed state, and it is feared that a roll may occur, the electromagnetic valve 7 is closed and the communication between the inside of the air spring 3 and the sub tank 6 is cut off.

Here, when the inside of the air spring 3 and the sub tank 6 are in communication with each other, the air volume in the air spring 3 becomes large, and the larger the air volume, the smaller the increase in the internal pressure against the external force. Therefore, the reaction force of the air spring 3 becomes small, and the spring constant becomes small, so that the roll easily occurs. On the other hand, the smaller the air volume of the air spring 3, the greater the increase of the internal pressure with respect to the external force. Therefore, by blocking the communication between the inside of the air spring 3 and the sub tank 6, the air volume of the air spring 3 is reduced. Since it is only inside 3, the reaction force becomes large, the spring constant becomes large, and it becomes difficult for rolls to occur.

Then, in step 6, when the steering angle θ becomes smaller than the second predetermined steering angle θy which is smaller than the predetermined steering angle θx, the steering angle of the steering becomes small and there is a fear that a roll will occur. Assuming that it is no longer present, the solenoid valve 7 is controlled to be opened so that the inside of the air spring 3 is communicated with the sub-tank 6 to improve the riding comfort. That is, the function of the control means is performed by the control unit 31.

As described above, in the present embodiment, only when the vehicle speed V is equal to or higher than the predetermined vehicle speed Vx and the steering angle θ is equal to or higher than the predetermined steering angle θx, the spring constant is increased to make the roll less likely to occur. Therefore, roll occurrence is suppressed only when there is a possibility of roll occurrence at high speed. That is, when turning back at a low speed, the spring constant remains small even if the steering angle θ is equal to or greater than the predetermined steering angle θx, so that the ride comfort is not impaired and passengers feel uncomfortable on a bus or the like. I will not let you. That is, as shown in FIG. 4, when there is a risk of a large roll, the solenoid valve 7 is controlled to be closed to reduce the roll as much as possible to improve traveling stability, and thereafter the solenoid valve 7 is controlled to be opened. And, it improves the riding comfort.

[0020]

[Effect of device]

 As described above, according to the present invention, in the vehicle air suspension device having the sub tank, when the vehicle speed and the steering angle of the steering are equal to or greater than a predetermined value, the communication with the sub tank is controlled to be closed. If there is a fear of rolling a large amount, it is possible to reduce rolling as much as possible and improve running stability.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a vehicle air suspension device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a control system according to the embodiment.

FIG. 3 is a flowchart illustrating the control content according to the embodiment.

FIG. 4 is a characteristic diagram illustrating an operation according to the embodiment.

FIG. 5 is a system configuration diagram of a conventional vehicle air suspension device.

[Explanation of symbols]

 3 Air spring 4 Leveling valve 5 Piping 6 Sub tank 7 Solenoid valve 31 Control unit 32 Vehicle speed sensor 33 Steering angle sensor

Claims (1)

[Scope of utility model registration request] 1. An air suspension device for a vehicle, comprising an air spring between an unsprung part and an unsprung part, and having a sub-tank communicating with the inside of the air spring. A vehicle speed detecting means for detecting a vehicle speed, a steering angle detecting means for detecting a steering angle of the steering wheel, and a control means for controlling the opening / closing means to be closed when the vehicle speed and the steering angle of the steering wheel are equal to or more than a predetermined value. An air suspension device for a vehicle, which is characterized in that